Re: vge(4) bad checksum

From: Kris Kennaway <kris_at_obsecurity.org>
Date: Sun, 17 Dec 2006 15:52:49 -0500
On Sun, Dec 17, 2006 at 11:46:24PM +0300, Andrew Pantyukhin wrote:
> I'm not sure what it's all about, but with today's
> current whatever goes out my vge interface (icmp/
> tcp/udp) has bad checksum:

This is a FAQ; it's probably using hardware checksum offloading.

Since the packet passed down to the NIC does not yet have the checksum
computed, it looks to tcpdump like the checksum is incorrect.  However
if you look at the packet actually transmitted by the NIC
(e.g. tcpdump on another host), you'll see that it has the correct
checksum.

Kris

Received on Sun Dec 17 2006 - 19:52:58 UTC

This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:39:04 UTC